union_vfsops.c revision 1.2
1 /* $NetBSD: union_vfsops.c,v 1.2 2003/03/17 09:11:31 jdolecek Exp $ */ 2 3 /* 4 * Copyright (c) 1994 The Regents of the University of California. 5 * Copyright (c) 1994 Jan-Simon Pendry. 6 * All rights reserved. 7 * 8 * This code is derived from software donated to Berkeley by 9 * Jan-Simon Pendry. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95 40 */ 41 42 /* 43 * Union Layer 44 */ 45 46 #include <sys/cdefs.h> 47 __KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.2 2003/03/17 09:11:31 jdolecek Exp $"); 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/time.h> 52 #include <sys/proc.h> 53 #include <sys/vnode.h> 54 #include <sys/mount.h> 55 #include <sys/namei.h> 56 #include <sys/malloc.h> 57 #include <sys/filedesc.h> 58 #include <sys/queue.h> 59 #include <sys/stat.h> 60 61 #include <fs/union/union.h> 62 63 int union_mount __P((struct mount *, const char *, void *, struct nameidata *, 64 struct proc *)); 65 int union_start __P((struct mount *, int, struct proc *)); 66 int union_unmount __P((struct mount *, int, struct proc *)); 67 int union_root __P((struct mount *, struct vnode **)); 68 int union_quotactl __P((struct mount *, int, uid_t, caddr_t, struct proc *)); 69 int union_statfs __P((struct mount *, struct statfs *, struct proc *)); 70 int union_sync __P((struct mount *, int, struct ucred *, struct proc *)); 71 int union_vget __P((struct mount *, ino_t, struct vnode **)); 72 int union_fhtovp __P((struct mount *, struct fid *, struct vnode **)); 73 int union_checkexp __P((struct mount *, struct mbuf *, int *, 74 struct ucred **)); 75 int union_vptofh __P((struct vnode *, struct fid *)); 76 int union_sysctl __P((int *, u_int, void *, size_t *, void *, size_t, 77 struct proc *)); 78 79 /* 80 * Mount union filesystem 81 */ 82 int 83 union_mount(mp, path, data, ndp, p) 84 struct mount *mp; 85 const char *path; 86 void *data; 87 struct nameidata *ndp; 88 struct proc *p; 89 { 90 int error = 0; 91 struct union_args args; 92 struct vnode *lowerrootvp = NULLVP; 93 struct vnode *upperrootvp = NULLVP; 94 struct union_mount *um = 0; 95 struct ucred *cred = 0; 96 char *cp; 97 int len; 98 size_t size; 99 100 #ifdef UNION_DIAGNOSTIC 101 printf("union_mount(mp = %p)\n", mp); 102 #endif 103 104 if (mp->mnt_flag & MNT_GETARGS) { 105 um = MOUNTTOUNIONMOUNT(mp); 106 if (um == NULL) 107 return EIO; 108 args.target = NULL; 109 args.mntflags = um->um_op; 110 return copyout(&args, data, sizeof(args)); 111 } 112 /* 113 * Update is a no-op 114 */ 115 if (mp->mnt_flag & MNT_UPDATE) { 116 /* 117 * Need to provide. 118 * 1. a way to convert between rdonly and rdwr mounts. 119 * 2. support for nfs exports. 120 */ 121 error = EOPNOTSUPP; 122 goto bad; 123 } 124 125 /* 126 * Get argument 127 */ 128 error = copyin(data, (caddr_t)&args, sizeof(struct union_args)); 129 if (error) 130 goto bad; 131 132 lowerrootvp = mp->mnt_vnodecovered; 133 VREF(lowerrootvp); 134 135 /* 136 * Find upper node. 137 */ 138 NDINIT(ndp, LOOKUP, FOLLOW, 139 UIO_USERSPACE, args.target, p); 140 141 if ((error = namei(ndp)) != 0) 142 goto bad; 143 144 upperrootvp = ndp->ni_vp; 145 146 if (upperrootvp->v_type != VDIR) { 147 error = EINVAL; 148 goto bad; 149 } 150 151 um = (struct union_mount *) malloc(sizeof(struct union_mount), 152 M_UFSMNT, M_WAITOK); /* XXX */ 153 154 /* 155 * Keep a held reference to the target vnodes. 156 * They are vrele'd in union_unmount. 157 * 158 * Depending on the _BELOW flag, the filesystems are 159 * viewed in a different order. In effect, this is the 160 * same as providing a mount under option to the mount syscall. 161 */ 162 163 um->um_op = args.mntflags & UNMNT_OPMASK; 164 switch (um->um_op) { 165 case UNMNT_ABOVE: 166 um->um_lowervp = lowerrootvp; 167 um->um_uppervp = upperrootvp; 168 break; 169 170 case UNMNT_BELOW: 171 um->um_lowervp = upperrootvp; 172 um->um_uppervp = lowerrootvp; 173 break; 174 175 case UNMNT_REPLACE: 176 vrele(lowerrootvp); 177 lowerrootvp = NULLVP; 178 um->um_uppervp = upperrootvp; 179 um->um_lowervp = lowerrootvp; 180 break; 181 182 default: 183 error = EINVAL; 184 goto bad; 185 } 186 187 /* 188 * Unless the mount is readonly, ensure that the top layer 189 * supports whiteout operations 190 */ 191 if ((mp->mnt_flag & MNT_RDONLY) == 0) { 192 error = VOP_WHITEOUT(um->um_uppervp, (struct componentname *) 0, LOOKUP); 193 if (error) 194 goto bad; 195 } 196 197 um->um_cred = p->p_ucred; 198 crhold(um->um_cred); 199 um->um_cmode = UN_DIRMODE &~ p->p_cwdi->cwdi_cmask; 200 201 /* 202 * Depending on what you think the MNT_LOCAL flag might mean, 203 * you may want the && to be || on the conditional below. 204 * At the moment it has been defined that the filesystem is 205 * only local if it is all local, ie the MNT_LOCAL flag implies 206 * that the entire namespace is local. If you think the MNT_LOCAL 207 * flag implies that some of the files might be stored locally 208 * then you will want to change the conditional. 209 */ 210 if (um->um_op == UNMNT_ABOVE) { 211 if (((um->um_lowervp == NULLVP) || 212 (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) && 213 (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL)) 214 mp->mnt_flag |= MNT_LOCAL; 215 } 216 217 /* 218 * Copy in the upper layer's RDONLY flag. This is for the benefit 219 * of lookup() which explicitly checks the flag, rather than asking 220 * the filesystem for it's own opinion. This means, that an update 221 * mount of the underlying filesystem to go from rdonly to rdwr 222 * will leave the unioned view as read-only. 223 */ 224 mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY); 225 226 mp->mnt_data = um; 227 vfs_getnewfsid(mp); 228 229 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 230 memset(mp->mnt_stat.f_mntonname + size, 0, MNAMELEN - size); 231 232 switch (um->um_op) { 233 case UNMNT_ABOVE: 234 cp = "<above>:"; 235 break; 236 case UNMNT_BELOW: 237 cp = "<below>:"; 238 break; 239 case UNMNT_REPLACE: 240 cp = ""; 241 break; 242 default: 243 cp = "<invalid>:"; 244 #ifdef DIAGNOSTIC 245 panic("union_mount: bad um_op"); 246 #endif 247 break; 248 } 249 len = strlen(cp); 250 memcpy(mp->mnt_stat.f_mntfromname, cp, len); 251 252 cp = mp->mnt_stat.f_mntfromname + len; 253 len = MNAMELEN - len; 254 255 (void) copyinstr(args.target, cp, len - 1, &size); 256 memset(cp + size, 0, len - size); 257 258 #ifdef UNION_DIAGNOSTIC 259 printf("union_mount: from %s, on %s\n", 260 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 261 #endif 262 263 /* Setup the readdir hook if it's not set already */ 264 if (!vn_union_readdir_hook) 265 vn_union_readdir_hook = union_readdirhook; 266 267 return (0); 268 269 bad: 270 if (um) 271 free(um, M_UFSMNT); 272 if (cred) 273 crfree(cred); 274 if (upperrootvp) 275 vrele(upperrootvp); 276 if (lowerrootvp) 277 vrele(lowerrootvp); 278 return (error); 279 } 280 281 /* 282 * VFS start. Nothing needed here - the start routine 283 * on the underlying filesystem(s) will have been called 284 * when that filesystem was mounted. 285 */ 286 /*ARGSUSED*/ 287 int 288 union_start(mp, flags, p) 289 struct mount *mp; 290 int flags; 291 struct proc *p; 292 { 293 294 return (0); 295 } 296 297 /* 298 * Free reference to union layer 299 */ 300 int 301 union_unmount(mp, mntflags, p) 302 struct mount *mp; 303 int mntflags; 304 struct proc *p; 305 { 306 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 307 struct vnode *um_rootvp; 308 int error; 309 int freeing; 310 311 #ifdef UNION_DIAGNOSTIC 312 printf("union_unmount(mp = %p)\n", mp); 313 #endif 314 315 if ((error = union_root(mp, &um_rootvp)) != 0) 316 return (error); 317 318 /* 319 * Keep flushing vnodes from the mount list. 320 * This is needed because of the un_pvp held 321 * reference to the parent vnode. 322 * If more vnodes have been freed on a given pass, 323 * the try again. The loop will iterate at most 324 * (d) times, where (d) is the maximum tree depth 325 * in the filesystem. 326 */ 327 for (freeing = 0; vflush(mp, um_rootvp, 0) != 0;) { 328 struct vnode *vp; 329 int n; 330 331 /* count #vnodes held on mount list */ 332 for (n = 0, vp = mp->mnt_vnodelist.lh_first; 333 vp != NULLVP; 334 vp = vp->v_mntvnodes.le_next) 335 n++; 336 337 /* if this is unchanged then stop */ 338 if (n == freeing) 339 break; 340 341 /* otherwise try once more time */ 342 freeing = n; 343 } 344 345 /* 346 * Ok, now that we've tried doing it gently, get out the hammer. 347 */ 348 349 if (mntflags & MNT_FORCE) 350 vflush(mp, um_rootvp, FORCECLOSE); 351 352 353 /* At this point the root vnode should have a single reference */ 354 if (um_rootvp->v_usecount > 1) { 355 vput(um_rootvp); 356 return (EBUSY); 357 } 358 359 #ifdef UNION_DIAGNOSTIC 360 vprint("union root", um_rootvp); 361 #endif 362 /* 363 * Discard references to upper and lower target vnodes. 364 */ 365 if (um->um_lowervp) 366 vrele(um->um_lowervp); 367 vrele(um->um_uppervp); 368 crfree(um->um_cred); 369 /* 370 * Release reference on underlying root vnode 371 */ 372 vput(um_rootvp); 373 /* 374 * And blow it away for future re-use 375 */ 376 vgone(um_rootvp); 377 /* 378 * Finally, throw away the union_mount structure 379 */ 380 free(mp->mnt_data, M_UFSMNT); /* XXX */ 381 mp->mnt_data = 0; 382 return (0); 383 } 384 385 int 386 union_root(mp, vpp) 387 struct mount *mp; 388 struct vnode **vpp; 389 { 390 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 391 int error; 392 int loselock; 393 394 /* 395 * Return locked reference to root. 396 */ 397 VREF(um->um_uppervp); 398 if ((um->um_op == UNMNT_BELOW) && 399 VOP_ISLOCKED(um->um_uppervp)) { 400 loselock = 1; 401 } else { 402 vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY); 403 loselock = 0; 404 } 405 if (um->um_lowervp) 406 VREF(um->um_lowervp); 407 error = union_allocvp(vpp, mp, 408 (struct vnode *) 0, 409 (struct vnode *) 0, 410 (struct componentname *) 0, 411 um->um_uppervp, 412 um->um_lowervp, 413 1); 414 415 if (error) { 416 if (!loselock) 417 VOP_UNLOCK(um->um_uppervp, 0); 418 vrele(um->um_uppervp); 419 if (um->um_lowervp) 420 vrele(um->um_lowervp); 421 } else { 422 if (loselock) 423 VTOUNION(*vpp)->un_flags &= ~UN_ULOCK; 424 } 425 426 return (error); 427 } 428 429 /*ARGSUSED*/ 430 int 431 union_quotactl(mp, cmd, uid, arg, p) 432 struct mount *mp; 433 int cmd; 434 uid_t uid; 435 caddr_t arg; 436 struct proc *p; 437 { 438 439 return (EOPNOTSUPP); 440 } 441 442 int 443 union_statfs(mp, sbp, p) 444 struct mount *mp; 445 struct statfs *sbp; 446 struct proc *p; 447 { 448 int error; 449 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 450 struct statfs mstat; 451 int lbsize; 452 453 #ifdef UNION_DIAGNOSTIC 454 printf("union_statfs(mp = %p, lvp = %p, uvp = %p)\n", mp, 455 um->um_lowervp, um->um_uppervp); 456 #endif 457 458 memset(&mstat, 0, sizeof(mstat)); 459 460 if (um->um_lowervp) { 461 error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, p); 462 if (error) 463 return (error); 464 } 465 466 /* now copy across the "interesting" information and fake the rest */ 467 lbsize = mstat.f_bsize; 468 sbp->f_blocks = mstat.f_blocks - mstat.f_bfree; 469 sbp->f_files = mstat.f_files - mstat.f_ffree; 470 471 error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, p); 472 if (error) 473 return (error); 474 475 sbp->f_type = 0; 476 sbp->f_flags = mstat.f_flags; 477 sbp->f_bsize = mstat.f_bsize; 478 sbp->f_iosize = mstat.f_iosize; 479 480 /* 481 * The "total" fields count total resources in all layers, 482 * the "free" fields count only those resources which are 483 * free in the upper layer (since only the upper layer 484 * is writable). 485 */ 486 487 if (mstat.f_bsize != lbsize) 488 sbp->f_blocks = sbp->f_blocks * lbsize / mstat.f_bsize; 489 sbp->f_blocks += mstat.f_blocks; 490 sbp->f_bfree = mstat.f_bfree; 491 sbp->f_bavail = mstat.f_bavail; 492 sbp->f_files += mstat.f_files; 493 sbp->f_ffree = mstat.f_ffree; 494 495 if (sbp != &mp->mnt_stat) { 496 memcpy(&sbp->f_fsid, &mp->mnt_stat.f_fsid, sizeof(sbp->f_fsid)); 497 memcpy(sbp->f_mntonname, mp->mnt_stat.f_mntonname, MNAMELEN); 498 memcpy(sbp->f_mntfromname, mp->mnt_stat.f_mntfromname, MNAMELEN); 499 } 500 strncpy(sbp->f_fstypename, mp->mnt_op->vfs_name, MFSNAMELEN); 501 return (0); 502 } 503 504 /*ARGSUSED*/ 505 int 506 union_sync(mp, waitfor, cred, p) 507 struct mount *mp; 508 int waitfor; 509 struct ucred *cred; 510 struct proc *p; 511 { 512 513 /* 514 * XXX - Assumes no data cached at union layer. 515 */ 516 return (0); 517 } 518 519 /*ARGSUSED*/ 520 int 521 union_vget(mp, ino, vpp) 522 struct mount *mp; 523 ino_t ino; 524 struct vnode **vpp; 525 { 526 527 return (EOPNOTSUPP); 528 } 529 530 /*ARGSUSED*/ 531 int 532 union_fhtovp(mp, fidp, vpp) 533 struct mount *mp; 534 struct fid *fidp; 535 struct vnode **vpp; 536 { 537 538 return (EOPNOTSUPP); 539 } 540 541 /*ARGSUSED*/ 542 int 543 union_checkexp(mp, nam, exflagsp, credanonp) 544 struct mount *mp; 545 struct mbuf *nam; 546 int *exflagsp; 547 struct ucred **credanonp; 548 { 549 550 return (EOPNOTSUPP); 551 } 552 553 /*ARGSUSED*/ 554 int 555 union_vptofh(vp, fhp) 556 struct vnode *vp; 557 struct fid *fhp; 558 { 559 560 return (EOPNOTSUPP); 561 } 562 563 int 564 union_sysctl(name, namelen, oldp, oldlenp, newp, newlen, p) 565 int *name; 566 u_int namelen; 567 void *oldp; 568 size_t *oldlenp; 569 void *newp; 570 size_t newlen; 571 struct proc *p; 572 { 573 return (EOPNOTSUPP); 574 } 575 576 extern const struct vnodeopv_desc union_vnodeop_opv_desc; 577 578 const struct vnodeopv_desc * const union_vnodeopv_descs[] = { 579 &union_vnodeop_opv_desc, 580 NULL, 581 }; 582 583 struct vfsops union_vfsops = { 584 MOUNT_UNION, 585 union_mount, 586 union_start, 587 union_unmount, 588 union_root, 589 union_quotactl, 590 union_statfs, 591 union_sync, 592 union_vget, 593 union_fhtovp, 594 union_vptofh, 595 union_init, 596 NULL, 597 union_done, 598 union_sysctl, 599 NULL, /* vfs_mountroot */ 600 union_checkexp, 601 union_vnodeopv_descs, 602 }; 603
Indexes created Mon Oct 13 08:09:50 GMT 2025